Aetna said by statement it would not comment on rumors or speculation. The insurer also did not comment on whether the subject would come up during its third quarter earnings call Tuesday at 8:30 a.m.
CVS Health also declined to comment, saying as a matter of policy, it doesn't comment on market rumors such as this.
CVS could benefit through gaining new members for its pharmacy benefit management arm and in negotiations with drugmakers, the WSJ report said.
CVS Health is the largest pharmacy chain in the nation, according to a 2016 list by Drug Channels. But Walgreens Boots Alliance, Express Scripts and Walmart are nipping at its heels for market share.
CVS's pharmacy retail pharmacy share is 14.8 percent, followed by Walgreens at 13.8 percent, the report said. In mail and specialty pharmacy business, CVS is behind Express Scripts, at an 8.6 percent market share of prescription revenues compared to 10.6 percent, respectively.
Its fiercest competition however, may come from Amazon, which is considering getting into the prescription pharmaceutical business.
Amazon Pharmacy could prove to be the leading disrupter in the healthcare industry, and was a subject broached by Cleveland Clinic CEO Toby Cosgrove during a recent Medical Innovation Summit.
"We are concerned about major forces, Amazon ... coming at us in purchasing," Cosgrove said. "Without significant consolidation on the part of providers, it's going to put us at a disadvantage. Fifty-five percent of hospitals in the U.S. lose money on patient care. We move on a very small margin."
To be more competitive, CVS Health has formed partnerships.
In August, CVS continued its march into primary care through an expansion of Minute Clinics in the greater New York City area, along with a broadening of its diabetes and chronic illness programs.
Aetna, coming off its failed $37 billion merger with Humana last year and the payment of a $1 billion breakup fee, reported a $381 million loss during the first quarter.
This week it announced it was selling The Hartford Group its group life and disability business for $1.45 billion.